One of the most common eye disorders, dry eye disease, causes irritation or discomfort, and can decrease functional vision, sometimes causing a dramatic deterioration in the quality of life. About five million Americans over age 50 suffer from moderate-to-severe dry eyes, and tens of millions more have mild or episodic manifestations of the disease, at a cost of more than $50 billion.

In terms of treatment, there are several drops and drugs that can help. We spend hundreds of millions of dollars on things like artificial tears, but currently there is no therapy available to actually fix the problem. If drugs don't work, doctors can try plugging up the outflow tear ducts, but that can cause complications, such as plugs migrating and eroding into the face, requiring surgical removal. Alternatively, surgeons can just cauterize or stitch up the ducts in the first place.

There has to be a better way.

What about prevention? Dry eyes can be caused by LASIK surgery, affecting about 20-40% of patients six months after the operation. With a million LASIK procedures performed annually, that's a lot of people, and sometimes the long-term symptoms can be severe and disabling.

There's a long list of drugs that can cause it, including antihistamines, decongestants, nearly all the antidepressants, anticonvulsants, antipsychotics, anti-Parkinson's drugs, beta-blockers, and hormone replacement therapy, as well as a few herbal preparations.

In the developing world, vitamin A deficiency can start out as dry eyes and then progress to becoming the leading cause of preventable childhood blindness. Vitamin A deficiency is almost never seen in the developed world, unless you do it intentionally. There was a report in the 1960s of a guy who deliberately ate a vitamin A-deficient diet, living off of bread and lime juice for five years, and his eyes developed vascularization and ulceration of the cornea, which you can see (if you dare) in my Treating Dry Eye Disease with Diet: Just Add Water?video.That was better than what happened to an unfortunate woman who was the member of a cult and tried to live off of brown rice and herbal tea: Her eyes literally melted and collapsed.

There are also a couple case reports of autistic children who refused to eat anything but French fries or menus exclusively comprised of bacon, blueberry muffins, and Kool-Aid, and became vitamin A deficient. A case in the Bronx was written up as vegan diet and vitamin A deficiency, but it had nothing to do with his vegan diet--the kid refused to eat vegetables, consuming only potato chips, puffed rice cereal with non-fortified soymilk, and juice drinks. "His parents lacked particular skill in overcoming the child's tendency to avoid fruits and vegetables."

A plant-based diet may actually be the best thing for patients with dry eye disease, those who wear contact lenses, and those who wish to maximize their tear secretions. People with dry eyes should be advised to lower protein, total fat, and cholesterol intake, and do the following:

We know dehydration can cause a dry mouth, but could dehydration cause dry eyes? It may seem kind of obvious, but evidently it was never studied until recently. Is the answer to just drink more water? We know that those suffering from dry eye are comparatively dehydrated, so researchers figured that tear secretion decreases with progressive dehydration just like saliva secretion decreases and gives us a dry mouth. And indeed, as one gets more and more dehydrated, their urine concentrates and so does the tear fluid. But one can reverse that with rehydration, raising the exciting prospect that improving whole-body hydration by getting people to drink more water might bring relief for those with dry eyes. The researchers recommend eight cups of water a day for women and ten cups a day for men.

One of the most common eye disorders, dry eye disease, causes irritation or discomfort, and can decrease functional vision, sometimes causing a dramatic deterioration in the quality of life. About five million Americans over age 50 suffer from moderate-to-severe dry eyes, and tens of millions more have mild or episodic manifestations of the disease, at a cost of more than $50 billion.

In terms of treatment, there are several drops and drugs that can help. We spend hundreds of millions of dollars on things like artificial tears, but currently there is no therapy available to actually fix the problem. If drugs don't work, doctors can try plugging up the outflow tear ducts, but that can cause complications, such as plugs migrating and eroding into the face, requiring surgical removal. Alternatively, surgeons can just cauterize or stitch up the ducts in the first place.

There has to be a better way.

What about prevention? Dry eyes can be caused by LASIK surgery, affecting about 20-40% of patients six months after the operation. With a million LASIK procedures performed annually, that's a lot of people, and sometimes the long-term symptoms can be severe and disabling.

There's a long list of drugs that can cause it, including antihistamines, decongestants, nearly all the antidepressants, anticonvulsants, antipsychotics, anti-Parkinson's drugs, beta-blockers, and hormone replacement therapy, as well as a few herbal preparations.

In the developing world, vitamin A deficiency can start out as dry eyes and then progress to becoming the leading cause of preventable childhood blindness. Vitamin A deficiency is almost never seen in the developed world, unless you do it intentionally. There was a report in the 1960s of a guy who deliberately ate a vitamin A-deficient diet, living off of bread and lime juice for five years, and his eyes developed vascularization and ulceration of the cornea, which you can see (if you dare) in my Treating Dry Eye Disease with Diet: Just Add Water?video.That was better than what happened to an unfortunate woman who was the member of a cult and tried to live off of brown rice and herbal tea: Her eyes literally melted and collapsed.

There are also a couple case reports of autistic children who refused to eat anything but French fries or menus exclusively comprised of bacon, blueberry muffins, and Kool-Aid, and became vitamin A deficient. A case in the Bronx was written up as vegan diet and vitamin A deficiency, but it had nothing to do with his vegan diet--the kid refused to eat vegetables, consuming only potato chips, puffed rice cereal with non-fortified soymilk, and juice drinks. "His parents lacked particular skill in overcoming the child's tendency to avoid fruits and vegetables."

A plant-based diet may actually be the best thing for patients with dry eye disease, those who wear contact lenses, and those who wish to maximize their tear secretions. People with dry eyes should be advised to lower protein, total fat, and cholesterol intake, and do the following:

We know dehydration can cause a dry mouth, but could dehydration cause dry eyes? It may seem kind of obvious, but evidently it was never studied until recently. Is the answer to just drink more water? We know that those suffering from dry eye are comparatively dehydrated, so researchers figured that tear secretion decreases with progressive dehydration just like saliva secretion decreases and gives us a dry mouth. And indeed, as one gets more and more dehydrated, their urine concentrates and so does the tear fluid. But one can reverse that with rehydration, raising the exciting prospect that improving whole-body hydration by getting people to drink more water might bring relief for those with dry eyes. The researchers recommend eight cups of water a day for women and ten cups a day for men.

According to the Centers for Disease Control and Prevention, the rates of all of our top 10 killers have fallen or stabilized except for one, suicide. As shown in my video, Antioxidants & Depression, accumulating evidence indicates that free radicals may play important roles in the development of various neuropsychiatric disorders including major depression, a common cause of suicide.

In a study of nearly 300,000 Canadians, for example, greater fruit and vegetable consumption was associated with lower odds of depression, psychological distress, self-reported mood and anxiety disorders and poor perceived mental health. They conclude that since a healthy diet comprised of a high intake of fruits and vegetables is rich in anti-oxidants, it may consequently dampen the detrimental effects of oxidative stress on mental health.

But that study was based on asking how many fruits and veggies people ate. Maybe people were just telling the researchers what they thought they wanted to hear. What if you actually measure the levels of carotenoid phytonutrients in people's bloodstreams? The same relationship is found. Testing nearly 2000 people across the United States, researchers found that a higher total blood carotenoid level was indeed associated with a lower likelihood of elevated depressive symptoms, and there appeared to be a dose-response relationship, meaning the higher the levels, the better people felt.

Lycopene, the red pigment predominantly found in tomatoes (but also present in watermelon, pink grapefruit, guava and papaya) is the most powerful carotenoid antioxidant. In a test tube, it's about 100 times more effective at quenching free radicals than a more familiar antioxidant like vitamin E.

Do people who eat more tomatoes have less depression, then? Apparently so. A study of about a thousand older men and women found that those who ate the most tomato products had only about half the odds of depression. The researchers conclude that a tomato-rich diet may have a beneficial effect on the prevention of depressive symptoms.

Higher consumption of fruits and vegetables has been found to lead to a lower risk of developing depression, but if it's the antioxidants can't we just take an antioxidant pill? No.

Only food sources of antioxidants were protectively associated with depression. Not antioxidants from dietary supplements. Although plant foods and food-derived phytochemicals have been associated with health benefits, antioxidants from dietary supplements appear to be less beneficial and may, in fact, be detrimental to health. This may indicate that the form and delivery of the antioxidants are important. Alternatively, the observed associations may be due not to antioxidants but rather to other dietary factors, such as folate, that also occur in plant-rich diets.

In a study of thousands of middle-aged office workers, eating lots of processed food was found to be a risk factor for at least mild to moderate depression five years later, whereas a whole food pattern was found to be protective. Yes, it could be because of the high content of antioxidants in fruits and vegetables but could also be the folate in greens and beans, as some studies have suggested an increased risk of depression in folks who may not have been eating enough.

Low folate levels in the blood are associated with depression, but since most of the early studies were cross-sectional, meaning a snapshot in time, we didn't know if the low folate led to depression or the depression led to low folate. Maybe when you have the blues you don't want to eat the greens.

But since then a number of cohort studies were published, following people over time. They show that a low dietary intake of folate may indeed be a risk factor for severe depression, as much as a threefold higher risk. Note this is for dietary folate intake, not folic acid supplements; those with higher levels were actually eating healthy foods. If you give people folic acid pills they don't seem to work. This may be because folate is found in dark green leafy vegetables like spinach, whereas folic acid is the oxidized synthetic compound used in food fortification and dietary supplements because it's more shelf-stable. It may have different effects on the body as I previously explored in Can Folic Acid Be Harmful?

These kinds of findings point to the importance of antioxidant food sources rather than dietary supplements. But there was an interesting study giving people high dose vitamin C. In contrast to the placebo group, those given vitamin C experienced a decrease in depression scores and also greater FSI. What is FSI? Frequency of Sexual Intercourse.

Evidently, high dose vitamin C improves mood and intercourse frequency, but only in sexual partners that don't live with one another. In the placebo group, those not living together had sex about once a week, and those living together a little higher, once every five days, with no big change on vitamin C. But for those not living together, on vitamin C? Every other day! The differential effect for non-cohabitants suggests that the mechanism is not a peripheral one, meaning outside the brain, but a central one--some psychological change which motivates the person to venture forth to have intercourse. The mild antidepressant effect they found was unrelated to cohabitation or frequency, so it does not appear that the depression scores improved just because of the improved FSI.

According to the Centers for Disease Control and Prevention, the rates of all of our top 10 killers have fallen or stabilized except for one, suicide. As shown in my video, Antioxidants & Depression, accumulating evidence indicates that free radicals may play important roles in the development of various neuropsychiatric disorders including major depression, a common cause of suicide.

In a study of nearly 300,000 Canadians, for example, greater fruit and vegetable consumption was associated with lower odds of depression, psychological distress, self-reported mood and anxiety disorders and poor perceived mental health. They conclude that since a healthy diet comprised of a high intake of fruits and vegetables is rich in anti-oxidants, it may consequently dampen the detrimental effects of oxidative stress on mental health.

But that study was based on asking how many fruits and veggies people ate. Maybe people were just telling the researchers what they thought they wanted to hear. What if you actually measure the levels of carotenoid phytonutrients in people's bloodstreams? The same relationship is found. Testing nearly 2000 people across the United States, researchers found that a higher total blood carotenoid level was indeed associated with a lower likelihood of elevated depressive symptoms, and there appeared to be a dose-response relationship, meaning the higher the levels, the better people felt.

Lycopene, the red pigment predominantly found in tomatoes (but also present in watermelon, pink grapefruit, guava and papaya) is the most powerful carotenoid antioxidant. In a test tube, it's about 100 times more effective at quenching free radicals than a more familiar antioxidant like vitamin E.

Do people who eat more tomatoes have less depression, then? Apparently so. A study of about a thousand older men and women found that those who ate the most tomato products had only about half the odds of depression. The researchers conclude that a tomato-rich diet may have a beneficial effect on the prevention of depressive symptoms.

Higher consumption of fruits and vegetables has been found to lead to a lower risk of developing depression, but if it's the antioxidants can't we just take an antioxidant pill? No.

Only food sources of antioxidants were protectively associated with depression. Not antioxidants from dietary supplements. Although plant foods and food-derived phytochemicals have been associated with health benefits, antioxidants from dietary supplements appear to be less beneficial and may, in fact, be detrimental to health. This may indicate that the form and delivery of the antioxidants are important. Alternatively, the observed associations may be due not to antioxidants but rather to other dietary factors, such as folate, that also occur in plant-rich diets.

In a study of thousands of middle-aged office workers, eating lots of processed food was found to be a risk factor for at least mild to moderate depression five years later, whereas a whole food pattern was found to be protective. Yes, it could be because of the high content of antioxidants in fruits and vegetables but could also be the folate in greens and beans, as some studies have suggested an increased risk of depression in folks who may not have been eating enough.

Low folate levels in the blood are associated with depression, but since most of the early studies were cross-sectional, meaning a snapshot in time, we didn't know if the low folate led to depression or the depression led to low folate. Maybe when you have the blues you don't want to eat the greens.

But since then a number of cohort studies were published, following people over time. They show that a low dietary intake of folate may indeed be a risk factor for severe depression, as much as a threefold higher risk. Note this is for dietary folate intake, not folic acid supplements; those with higher levels were actually eating healthy foods. If you give people folic acid pills they don't seem to work. This may be because folate is found in dark green leafy vegetables like spinach, whereas folic acid is the oxidized synthetic compound used in food fortification and dietary supplements because it's more shelf-stable. It may have different effects on the body as I previously explored in Can Folic Acid Be Harmful?

These kinds of findings point to the importance of antioxidant food sources rather than dietary supplements. But there was an interesting study giving people high dose vitamin C. In contrast to the placebo group, those given vitamin C experienced a decrease in depression scores and also greater FSI. What is FSI? Frequency of Sexual Intercourse.

Evidently, high dose vitamin C improves mood and intercourse frequency, but only in sexual partners that don't live with one another. In the placebo group, those not living together had sex about once a week, and those living together a little higher, once every five days, with no big change on vitamin C. But for those not living together, on vitamin C? Every other day! The differential effect for non-cohabitants suggests that the mechanism is not a peripheral one, meaning outside the brain, but a central one--some psychological change which motivates the person to venture forth to have intercourse. The mild antidepressant effect they found was unrelated to cohabitation or frequency, so it does not appear that the depression scores improved just because of the improved FSI.

Maria Fernandez has received nearly a half million dollars from the egg industry and writes papers like "Rethinking dietary cholesterol." She admits that eggs can raise LDL cholesterol, bad cholesterol, but argues that HDL, so-called "good cholesterol," also rises, thereby maintaining the ratio of bad to good. To support this assertion, she cites one study that she performed with Egg Board money that involved 42 people.

If we look at a meta-analysis, a measure of the balance of evidence, the rise in bad is much more than the rise in good with increasing cholesterol intake. The analysis of 17 different studies showed that dietary cholesterol increases the ratio of total to HDL cholesterol, suggesting that the favorable rise in HDL fails to compensate for the adverse rise in total and LDL cholesterol. Therefore, increased intake of dietary cholesterol from eggs may indeed raise the risk of coronary heart disease.

The Egg Board responded (as seen in my video, Does Cholesterol Size Matter?) by saying that the increased heart disease risk associated with eating eggs needs to be put in perspective relative to other risk factors, arguing that it's worse to be overweight than it is to eat eggs, to which the authors of the meta-analysis replied, "Be that as it may, many people do not find it a major hardship to cut back on egg intake, whereas most people find it impossible to lose weight permanently."

Fine, Fernandez admitted, eggs increase LDL, but she claims that the increase is in large LDL, arguing that large, fluffy LDL particles are not as bad as small, dense particles. Indeed, large LDL only raises heart disease risk of women by 44%, instead of 63% for small LDL. Light large buoyant LDL still significantly increases our risk of dying from our #1 killer. The difference is similar for men: large LDL only increases risk of heart attack or death by 31%, instead of 44%. As the latest review on the subject concluded, LDL cholesterol has "clearly been established as a causal agent in atherosclerosis ... Regardless of size, LDL particles are atherogenic." Yet Egg Board researcher, Fernandez, wrote that the formation of larger LDL from eggs is considered protective against heart disease, relative to small LDL. That's like saying getting stabbed with a knife is protective--relative to getting shot!

Health practitioners should bear in mind, she writes, that "restricting dietary cholesterol puts a burden on egg intake" and leads to the avoidance of a food that contains dietary components like carotenoids and choline. She wrote this in 2012, before the landmark 2013 study showing that choline from eggs appears to increase the risk of stroke, heart attack, and death, so she can be excused for that. But what about the carotenoids in eggs, like lutein and zeaxanthin, which are so important for protecting vision and reducing cholesterol oxidation? As I explored previously, the amounts of these phytonutrients in eggs are miniscule. One spoonful of spinach contains as much as nine eggs. Comparing the predictable effects on eye health of organic free-range eggs versus corn and spinach, the effect of eggs is tiny.

What about the effects of eggs on cholesterol oxidation? We've known for decades that LDL cholesterol is bad, but oxidized LDL is even worse. Therefore, according to Fernandez, since eggs have trace amounts of antioxidants, eggs may prevent cholesterol oxidation. But the science shows the exact opposite. Consumption of eggs increases the susceptibility of LDL cholesterol to oxidation. The researchers found that not only does eating eggs raise LDL levels, but also increases LDL oxidizability, in addition to the oxidizability of our entire bloodstream. This was published 18 years ago, yet Fernandez still tries to insinuate that eggs would reduce oxidation.

She acknowledges receiving funding from the American Egg Board, and then claims she has no conflicts of interest.

This is why a site like NutritionFacts.org can be so useful, because even when a paper is published in the peer-reviewed medical literature, it can misrepresent the science. But who has time to check the primary sources? I do! If you'd like to support this work, please consider making a tax-deductible donation.

Here are some other videos in which I contrast the available science with what the egg industry asserts:

In my video Breast Cancer and Constipation, I discussed how fruits and veggies bind carcinogenic bile acids in our gut. Since bile acids are absorbed back into our systems, they may increase our risk of not only colon cancer but also other cancers as well. In light of this, researchers publishing in the journal, Nutrition Research, concluded that to "lower the risk of diet and lifestyle-related premature degenerative diseases and to advance human nutrition research, relative bile acid-binding potential of foods and fractions need to be evaluated."

They found that some vegetables bind bile acids better than others. We know that those eating more plant-based diets are at a lower risk of heart disease and cancer. This could partly be because of phytonutrients in plants that act as antioxidants and potent stimulators of natural detoxifying enzymes in our bodies. Veggies can also lower cholesterol and detoxify harmful metabolites, functions that can be predicted by their ability to bind bile acids.

A group of USDA researchers studying this topic discovered three important things. First, they found an over five-fold variability in bile acid binding among various vegetables that had similar fiber content, suggesting that bile acid binding is not just related to total dietary fiber content (as previously thought), but instead some combination of unique phytonutrients yet to be determined.

Second, they discovered that steaming significantly improves the bile acid binding of collards, kale, mustard greens, broccoli, peppers, cabbage, beets, eggplant, asparagus, carrots, green beans, and cauliflower, suggesting that in this way steaming vegetables may be more healthful than those consumed raw.

Finally, they ranked multiple vegetables for bile binding ability. Which vegetables kicked the most bile butt? (in my video, Which Vegetable Binds Bile Best?, you can see a visual comparison of bile binding ability.) Turnips turned up last. Then came cabbage, cauliflower, bell peppers, spinach, asparagus and green beans. Mustard greens and broccoli were better. Eggplant, carrots and Brussels sprouts basically tie for the #5 slot. Then collards at #4. Kale got the bronze, okra the silver, and beets the gold. Kale, surprisingly, got beet.

The researchers concluded that inclusion of all these vegetables in our daily diets should be encouraged. When consumed regularly, they concluded, these vegetables may lower the risk of premature degenerative diseases and improve public health.

Anyone who has gotten a bad sunburn knows how damaging the UV rays in sunlight can be. Imagine what those same rays are doing to back of our eyeballs (our retinas). The eye is designed to take sunlight and focus it like a magnifying glass into the back of our eyes. Thankfully, we have a layer of cells called the retinal pigment epithelium that supports and protects our delicate retinal eyesight machinery. The layer builds up yellow plant pigments like zeaxanthin from our diet, absorbing blue light and protecting the retina from photo-oxidative damage. The yellowing of our corneas when we develop cataracts may actually be our bodies' defense mechanism to protect our retinas. In fact, when cataracts are removed, the risk of blindness from macular generation shoots up (because we removed the protection). Instead of trading one type of vision loss for another, it's better to pigment the back of our eyes through diet instead of pigmenting the front of our eyes with cataracts. The pigment in the back of our eyes is entirely of dietary origin, "suggesting that the most common cause of blind registration in the Western World could be delayed, or even averted, with appropriate dietary modification," according to authors of a study on age-related macular degeneration.

Where in our diet do we get these pigments? The egg industry brags that eggs are a good source, but have nearly six high-lutein, free-range, certified organic eggs a week for three months and the pigmentation in one's eyes may only marginally increase (see Egg Industry Blind Spot). Instead of getting the phytonutrients from the egg that came from the chicken that came from the corn and blades of grass the chicken pecked on, we could get it from the source. One cup of corn and a half cup of spinach a day for three months seems to dramatically boost the protective eye pigment in subjects. In the video, Dietary Prevention of Age Related Macular Degeneration, you can see a comparison of the amount of these phytonutrients from eggs compared to corn and spinach. If we cut out the middlehen and get these nutrients from plants directly, we see a substantially larger increase in protective eye pigment.

Three months after the subjects stopped eating the corn and spinach, the levels of these pigments remained relatively high, indicating that once we build our macular pigment up with a healthy diet, our eyeballs really try to hold on to it. So even if we go on vacation and end up eating more iceberg lettuce than spinach, our eyes will hold out until we get back.

Eggs can increase zeaxanthin levels in the blood, but they can also raise bad cholesterol levels and increase the risk of heart disease. Thus, as researchers conclude, "an egg yolk-based dietary strategy to increase plasma zeaxanthin cannot be recommended, and an alternative, cholesterol-free, food source is desirable." One such alternative would be goji berries, which have up to 60 times more zeaxanthin than eggs. A modest dose of goji markedly increases levels in our body. Consumption of goji berries may be an effective, safe whole food strategy to increase zeaxanthin in the bloodstream.

But we don't need it in our blood, we need it in our eyes. A group of researchers performed a double-blind randomized placebo-controlled trial to test the effectiveness of goji berries at increasing pigment levels. To preserve eyesight in the elderly in traditional Chinese medicine, people are often prescribed 40 to 100 goji berries a day. In this study, participants consumed only about 15 berries a day for three months. Even at this small dose researchers found that goji berries could protect against loss of pigment and prevent the buildup of debris that builds up in the back of the eye. Both loss of pigment and debris buildup are associated with age-related macular degeneration.

Macular degeneration is the leading cause of legal blindness in older men and women, affecting more than ten million Americans, so increasing our consumption of these pigments as a society could significantly decrease the prevalence of blindness. In the above study, researchers gave the goji berries in milk so the butterfat could increase the absorption of these carotenoid pigments. A healthier way to get the same effect would just be to eat goji berries with nuts or seeds--in other words, goji trail mix.

If traditional Potato Salad was in a midlife crisis and its therapist asked, “What would you be if you could be anything in the world,” it might say “Curried Sweet Potato Salad!” It’s distinctive, daring, and delectable, not to mention, attractive! Ingredients Dressing: 1/2 cup raw, unsalted cashews (2 ounces) 1/2 cup water 1/4 cup […]

Ah, lovely pesto! Summer is here and so is the fresh basil. “But don’t you need oil and cheese to make pesto?” No way! These ingredients are traditional, but they can be simply omitted, resulting in a sauce that is much lighter and fresher in taste. Pesto is an Italian oil-and-herb sauce, with garlic, pine […]